Hub and strut in a reticulated frame

ABSTRACT

A plurality of hubs are joined to frame struts thereby forming a space frame structure, wherein the hubs have monolithic bodies with protruding joints adapted for receiving and joining with the frame struts using tubular sleeves. Axes of the joints are aligned to converge at a common point to avoid rotational moment forces on the hubs. The hubs are preferably fabricated by a 3D printing method in a structural material. In a method of the invention, the struts, joint diameters and joint lengths are sized and positioned to avoid interference between adjacent struts.

PRIOR PATENT INFORMATION RELATIVE TO THE INVENTION

Application 61/503,323 filed Jun. 30, 2011; application Ser. No.13/540,449 filed Jul. 2, 2012 and issued as U.S. Pat. No. 8,820,025B1 onSep. 2, 2014. The prior patent discloses a similar invention to thatwhich is disclosed herein. The inventor is common to both.

FIELD OF THE DISCLOSURE OF THE INVENTION

The field of this invention relates to reticulated frame structures andspace frames, and particularly to a novel hub capable of joiningstructural frame elements of such structures.

BACKGROUND AND PRIOR ART OF THE INVENTION

A reticulated frame is often referred to as a space frame because it iscapable of covering large spaces with little interior support. It istypically a lightweight rigid structure having interlocking strutsconnected to hubs in a geometric pattern similar to a bridge truss. Likethe well-known truss, such frames are strong because of the inherentrigidity of triangular beam arrangements where flexing loads and bendingmoments are transmitted as tension and compression vectors along thelength of the beams. Such frames are common in building constructionsuch as large roof spans in modern commercial and industrial buildings.Notable examples are the Stansted airport terminal in London, the Bankof China Tower, the Louvre Museum Pyramid, the Rogers Centre in Toronto,Ontario, and McCormick Place Lakeside Center in Chicago, Ill., USA.Large portable stages and lighting gantries are frequently built fromsuch frames with octet trusses which are the structures of choice forholding signs above roads and in stadiums. The following documents havecited my prior patent U.S. Pat. No. 8,820,025B1 and are considered priorart in this application: US20150059263A1 and US9212479B1 to DevrimPacaci, entitled “Supporting Framework Having Connection Hubs;”US20-150101645A1 to Garden Right, LLC, entitled “Dome Flubs, DomeAssembly Kits, and Dome Assembly Methods” CN106592762A to

entitled Space assembling type bolt-column joint;“. CN106760235A to

entitled Kind Of Multidirectional Adjustable Curved Surface LightingRoof Grid System;” US20170167516A1 to Paul H. Mason, entitled “StrutConnector;”. US9731773B2 to Caterpillar Inc. entitled “-Node For A SpaceFrame;”. DE102016010883A1 to Technische Universitätm Chemnitz Variable,entitled “Connection Element,” CN110578370A to

entitled “Bolt Ball For Steel Structure Connection;”. US20200109549A1 toManuel Fernando and Bethencourt Cravid entitled “Lattice Structure”; andCNI 11042318A to

, entitled “Single-Layer Aluminum Alloy Latticed Shell Box Type ModularAssembly Joint And Construction Process Thereof.”

SUMMARY OF THE INVENTION

It should be recognized that the prior art does not teach a framestructure whereby frame elements converge to transfer loads to and froma common point at a hub thereby avoiding rotational moments in the hub.The invention teaches structure and methods whereby beam loads aretransferred axially to hubs. This approach is beneficial in its abilityto enable a direct load transfer between load bearing members mutuallyterminated within a common hub. The presently described hub is anessential joining element in the construction and operation of frames ofthe type described and shown. Uniquely, the hub is a one piecemonolithic element functional as a node within a frame structure. Inpractice, a hub may be a terminal point within a frame structure, or itmay join two or more struts of the frame. In one aspect of the presentlydescribed apparatus, the longitudinal axes of all struts which arejoined to a single common hub pass through a common point. This avoidsthe possibility of force moments on, or within, the hub, important forpassing tensile and compressive forces along the frame without unwantedstress being applied to the frame and without generating bending orshear forces on the struts or hubs. In another aspect of the invention,the axis of each strut is coaxial with a radius of a theoretical sphereof the hub body and may be selectively positioned within a range ofangular positions all the while remaining co-radial with the theoreticalsphere. Of course, this accounts for the benefit described in thepreceding. In another aspect of the invention, the angular range ofpositions of each one of the struts relative to their connected hubs maybe between 45° and 90°. In another aspect of the invention, each of thefasteners may have a threaded stud or a threaded entry and may berotatable about its radially aligned axis thereby providing a simple andquick means for securely attaching one end of a strut to the fastenerwherein the strut may be adapted for threadedly engaging the fastener.In another aspect of the invention, each one of the hubs may berotatable enabling any position within a solid angle having a cone outersurface defined by the angular range of the possible extreme positionsof the fastener. The details of one or more embodiments of theseconcepts are set forth herein and other features, objects, andadvantages of these concepts will be apparent to those of skill in theart from this writing and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS OF THE INVENTION

Embodiments of the invention are illustrated only as examples in thedrawing figures accompanying this written description. Alpha-numericalcall-outs are used to identify elements of the invention, wherein thesame call-out refers to the same element as it may appear in variousviews of the figures.

FIG. 1 is a perspective view of a frame structure of the invention;

FIG. 2 is a section view of a hub thereof;

FIG. 3 is a perspective view of the hub of FIG. 2 ;

FIG. 4 is an elevation view thereof;

FIG. 5 is a further elevation view thereof;

FIG. 6 is an expanded partial section view of a strut-connector-hub ofthe invention;

FIG. 7 illustrates FIG. 6 with strut-connector-hub joined; and

FIG. 8 is a perspective view of a hub interconnected with struts of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

In an embodiment of the invention, a frame structure (frame 5) is shownin FIG. 1 and comprises a plurality of struts 50 engaged with aplurality of hubs 10 making up a structure which may be quite large andmay have a desired overall shape or appearance. Although not describedhere, frame 5 may have panels and similar structure attached andincorporated therewith forming walls, floors and other useful buildingfeatures. The designer or architect of frame 5 will consider thetopography of the surface on which frame 5 is to be supported as well asloads due to wind and other natural forces including potential surfacemovements, and also bearing loads, and stress and strain factors withinframe 5 due to its own weight and to possible loads and external forces.These considerations are well-known in structural engineering practiceand can be calculated using standard methods. As will be understood,hubs 10 within frame 5 are the elements to which all struts 50 attachand are therefore the “glue” which holds frame 5 together in its desiredconfiguration. Struts 50 may be made of metal, polymer materials,resins, nanotubes, fiber reinforced composites, and other engineeringmaterials and may be solid beams or hollow with circular, rectangular orother cross sectional shapes; see FIG. 8 . Each of the two opposite ends52 of each strut 50 may be engaged with a hub joint 10A, 10B, or 10Cwhich are best shown in FIGS. 2 through 5 . In this description furtherreference to hub joints shall be designated by “10 x” which shall meanone or more than one such hub joints. Each one of hubs 10 comprises amonolithic body with at least two, but possibly more than two, integralhub joints 10 x. In order to provide maximum flexibility in placement ofstruts 50 within frame 5, it is desirable that hubs 10 be able toaccommodate (receive and connect with) struts 50 arriving from a widerange of directions. This permits the total number of components(struts, hubs) to be minimized, thus minimizing costs. This, in turn,requires that hub joints 10 x have the largest number and greatest rangeof possible angular positions on hubs 10. In order to accommodate struts50 that are near or adjacent to one another at any hub 10, it isnecessary to use length L, as shown in FIG. 2 , as a design parameterand as a means of providing strut-to-strut clearance at any given hub10. Further, it should be understood that by using a minimum possiblelength L for all hub joints 10 x, hub manufacturing time and materialusage, and overall weight and cost of frame 5 are minimized. This can beof significant commercial benefit. Now, referring to FIGS. 2-5 , we seein FIG. 2 that in hub 10 the direction of each hub joint 10 x is definedby its vector 12. That being the case, then it is obvious that each twoadjacent vectors 12 define a plane in 3-space and if the sizes of struts50, hardware elements 40, 42 and sleeve 20 (see FIGS. 6 and 7 ) areknown, the minimal length L to afford clearance between adjacent struts50 may be determined by graphical or algebraic methods in order toassure adjacency clearance. Each one of hub joints 10 x is adapted, in amanner to be described, for engaging an end 52 of one of struts 50 asshown in FIGS. 6 and 7 . Axes of each one of hub joints 10 x mutuallyconverge on a common point 14 as shown in FIG. 2 . With respect to eachhub 10, its hub joints 10 x are preferably positioned such that axes 12all converge on common point 14. Therefore, force moments on hubs 10 areavoided which assures that hubs 10 do not tend to rotate which coulddamage the components as well as frame 5 itself. At least one of hubjoints 10 x may be a tubular projection of the monolithic body of hub10. Struts 50 may be of disparate sizes and hub joints 10 x may likewisebe of disparate sizes corresponding to the sizes of struts 50, see, forinstance, FIG. 2 . Hubs 10 are preferably fabricated by 3D printingmethods and may be made of hard polymers or metals. They can also beproduced by processes such as molding, machining and stamping. Struts 50may be linear in form with two opposing ends 52 wherein each of theseends 52 may be joined with one of hub joints 10 x by a tubular sleeve 20as shown in FIGS. 6 and 7 . As shown tubular sleeves 20 may be fastenedto one of hub joints 10 x by an axially oriented fastener such as bolt30 and to strut 50 by a transaxially oriented fastener 40 and nut 42.This is considered to be a novel arrangement but it will be possible forthose of skill in the mechanical arts to arrange different attachmentschemes. In an embodiment of the invention, a method of producing frame5 may include engaging a plurality of struts 50 with a plurality of hubs10 in a manner shown in FIGS. 6 and 7 . This may involve forming each ofhubs 10 as a monolithic body having plural hub joints 10 x and adaptingeach one of hub joints 10 x for engaging an end 52 of one of struts 50by using a tubular sleeve 20. Hub joints 10 x may be positioned so thataxes 12 are mutually convergent on point 14 as shown in FIG. 2 . Themethod may include producing hub joints 10 x as tubular projectionsintegral to the monolithic body of hub 10. The struts 50 of frame 5 maybe produced in sizes, of materials, and of cross-sectional design asrequired by their load carrying functions.

Embodiments of the subject apparatus and method of this invention havebeen described herein. Nevertheless, it will be understood that variousmodifications may be made without departing from the spirit andunderstanding of this disclosure. Accordingly, other embodiments andapproaches are within the scope of the following claims.

What is claimed is:
 1. A frame structure comprising: a plurality ofstruts engaged with a plurality of hubs; each of said hubs comprising amonolithic body with at least two integral hub joints integrally formedwith said monolithic body; wherein each one of said hub joints isadapted for engaging an end of one of said struts; and wherein axes ofsaid hub joints mutually converge.
 2. The frame structure of claim 1wherein at least one of said hub joints is an integral tubularprojection extensive from said monolithic body.
 3. The frame structureof claim 1 wherein said struts are of disparate sizes.
 4. The framestructure of claim 3 wherein said hub joints are of disparate sizescorresponding to said disparate sizes of said struts.
 5. The framestructure of claim 1 wherein at least one of said hubs is a product of a3D printing method.
 6. The frame structure of claim 1 wherein said endof said one of said struts is joined with one of said hub joints by atubular sleeve.
 7. The frame structure of claim 6 wherein said tubularsleeve is fastened to said one of said hub joints by an axially orientedfastener and to said strut by a transaxially oriented fastener.
 8. A hubfor integration into a frame structure said hub comprising: a monolithicbody with at least two integral hub joints; wherein each one of said hubjoints is adapted for engaging an end of a strut of said framestructure; and wherein axes of said hub joints mutually converge.
 9. Thehub of claim 8 Wherein at least one of said hub joints is a tubularprojection relative to said monolithic body.
 10. The hub of claim 9wherein said hub joints are of disparate sizes.
 11. The hub of claim 10wherein said hub is a product of a 3D printing method.
 12. A method ofproducing a frame structure wherein said method comprises: engaging aplurality of struts with a plurality of hubs; forming each one of saidhubs into a monolithic body having at least two integral hub joints;adapting each one of said hub joints for engaging an end of one of saidstruts; and positioning said hub joints wherein axes of said hub jointsmutually converge.
 13. The method of claim 12 wherein said hub jointsare produced as tubular projections of said monolithic body and saidtubular projections are minimized in length.
 14. The method of claim 13wherein said struts are produced with disparate sizes.
 15. The method ofclaim 14 wherein said hub joints are produced with disparate sizescorresponding to said disparate sizes of said struts.
 16. The method ofclaim 12 wherein at least one of said hubs is produced by a 3D printingmethod.
 17. The method of claim 12 wherein a tubular sleeve ispositioned for joining said end of said one of said struts with said oneof said hub joints.
 18. The method of claim 17 wherein an axiallyoriented fastener is positioned for joining said tubular sleeve to saidone of said hub joints.
 19. The method of claim 17 wherein atransaxially oriented fastener is positioned for joining said tubularsleeve to said one of said struts.